Start-Up - Allied Air 4SCU14LE SERIES Installation And Maintenance Instructions Manual

START-UP

If unit is equipped with a crankcase heater, it should be
energized 24 hours before unit start-up to prevent
compressor damage as a result of slugging.
1. Rotate fan to check for frozen bearings or binding.
2. Inspect all factory and field-installed wiring for loose
connections.
3. After evacuation is complete, open liquid line and suction
line service valves to release refrigerant charge
(contained in outdoor unit) into system.
4. Replace the stem caps and secure finger tight, then
tighten an additional 1/6 of a turn.
5. Check voltage supply at the disconnect switch. The
voltage must be within the range listed on the unit
nameplate. If not, do not start equipment until the power
company has been consulted and the voltage condition
corrected.
6. Set thermostat for cooling demand, turn on power to
indoor blower and close the outdoor unit disconnect
switch to start the unit.
7. Recheck unit voltage with unit running. Power must be
within range shown on unit nameplate.
Refrigerant Charging
This system is charged with R410A refrigerant which operates
at much higher pressures than R22. The liquid line drier provided
with the unit is approved for use with R410A. Do not replace it
with one designed for use with R22. This unit is NOT approved
for use with coils which use capillary tubes as a refrigerant
metering device.
R410A refrigerant cylinders are rose colored. Refrigerant
should be added through the vapor valve in the liquid
state.
Certain R410A cylinders are identified as being equipped
with a dip tube. These allow liquid refrigerant to be
drawn from the bottom of the cylinder without inverting
the cylinder. Do not turn this type of cylinder upside
down to draw refrigerant.
Units are factory charged with the amount of R410A
refrigerant indicated on the unit rating plate. This charge is
based on a matching indoor coil and outdoor coil with 15'
Page 12 of 20
CAUTION
Refrigerant Charge Adjustment
Liquid Line Set
Diameter
3/8 in.
* If line length is greater than 15 ft., add this amount.
If line length is less than 15 ft., remove this amount.
Mineral oils are not compatible with R410A. If oil must be
added, it must be a polyol ester oil.
line set. For varying lengths of line set, refer to Table 4 for
refrigerant charge adjustment.
If the system is void of refrigerant, clean the system using
the procedure described below.
1. Use dry nitrogen to pressurize the system and check
for leaks. Repair leaks, if possible.
2. Evacuate the system to remove as much of the moisture
as possible.
3. Use dry nitrogen to break the vacuum.
4. Evacuate the system again.
5. Weigh the appropriate amount of R410A refrigerant
(listed on unit nameplate) into the system.
6. Monitor the system to determine the amount of moisture
remaining in the oil. Use a test kit to verify that the
moisture content is within the kit's dry color range. It
may be necessary to replace the filter drier several times
to achieve the required dryness level. If system dryness
is not verified, the compressor will fail in the future.
The outdoor unit should be charged during warm weather.
However, applications arise in which charging must occur in
the colder months. The method of charging is determined
by the outdoor ambient temperature.
Measure the liquid line temperature and the outdoor ambient
temperature as outlined below:
1. Connect the manifold gauge set to the service valve
ports as follows:
• Low pressure gauge to suction line service valve
Issue 1015
Oz. per 5 ft. adjust
from 15 ft. line set *
3 oz. per 5 ft.
Table 4
IMPORTANT
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